"The lines between the Mac OS and Windows are starting to blur. And that portends major changes going forward in the world of PCs. At last week's MacWorld, a little company called Parallels won awards for the latest version of its hit product, which enables you to run both operating systems at the same time on a Macintosh. It's a major breakthrough."

That comparison would be valid if not for the fact that a BMW is different from a Renault not only on the outside, but also on the inside. Your comparison would make sense if BMW just put different bodies on existing Renault or whatever platforms and engines; instead, BMW develops everything in-house, and builds everything in-house.

BMW does not develop everything in-house. For example the breaks are OEM from Brambo. The same goes for the air-conditioner and radiator.